Safety in ESD rooms and high voltage measurements

We as IONIO often come into an environment where we supply test and measurement systems in ESD rooms. An ESD room is a dedicated workspace designed to prevent damage from Electrostatic Discharge (ESD).

ESD is the discharge of static electricity that can damage electronic components. This type of room is often used in the electronics industry, for example in the production, repair, or assembly of sensitive electronic devices and components.

Electrical safety tests are also often carried out in these areas and we are often asked how to set this up safely, of course, as described in EN50191, the best solution is by applying direct protection such as a test cage.

In many cases, this is not possible due to dimensions of the test object and/or the level of investment required.

In ESD areas, it is desirable to have good grounding by using ESD shoes, among other things, ESD shoes have an electrical resistance between 0.1 and 100 (MΩ) to ensure a controlled discharge of static electricity.

Why are ESD shoes not suitable for high voltage?

When working with high voltage, the aim is to completely isolate a person from the earth so that no current path is created.

However, ESD shoes are more conductive compared to standard footwear and therefore do not provide protection against electric shock. In fact, they may pose a hazard as they may conduct current to earth faster.

• Conflict in function:
  • High-voltage protection: Insulate the body to prevent current passage.
  • ESD protection: conductive properties to dissipate static electricity.

• Risk in use: In contact with high voltage, ESD shoes can increase the risk because they offer lower resistance, allowing current to flow through the body to the ground.

Alternatives for combined needs

In environments where both high-voltage and ESD protection are required, the following measures may be considered:

1. Separating work zones: Create separate work areas for high-voltage testing and ESD-sensitive work.
2. Protective insulation mats: Use insulating mats with specific properties that are safe for high voltage and comply with standard IEC 61111 (insulating mats).
3. Use insulating shoes: At high voltage, shoes with a high insulation value are preferred, as this often conflicts with an ESD room, using insulating mats according to IEC 61111 is a better solution.

Conclusion

ESD shoes should preferably not be used in high-voltage environments due to their conductive properties if there is no possibility of direct protection of the test setup. Alternatively, isolation mats can be applied according to IEC 61111.

Standard IEC 61111 divides insulating mats into different classes depending on the maximum working voltage for which they are suitable. Each class has specific testing requirements: